Inflatable gripper for handling spools of textile machines

ABSTRACT

In a mandrel-like gripper assembly for firmly engaging the inner wall of a hollow spool, the inflatable hollow gripper body is formed of an expandable, resilient wall having, in cross section, an undulating, closed configuration.

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United. States Patent 1 1 1 Rothke 1 51 Feb. 6, 1973 [54] INFLATABLE GRIPPER FOR [SE/i iefel'eiicz ifi WWW m h Mwvnflw HANDLING SPOOLS OF TEXTILE NI E P MACHINES U TED STAT S ATENTS 3,367,098 2/1968 Schulz ..57/52 Schmndmf, Germany 3,462,934 8/1969 Schulz et al. ..57 52 [73] Assignee: Zinser-Textilmaschinen Gesellschaft mit beschrankter H ft Eber- Primary Examiner-John Petrakes sbach, Gel-many Attorney-Edwin E. Greigg Filed: NOV. 9, 1970 [2]] Appl. No.1 87,873 In a mandrel-like gripper assembly for firmly engaging the inner wall of a hollow spool, the inflatable hollow [30] Foreign Application Priority Data gripper body is formed of an expandable, resilient wall having, in cross section, an undulating, closed configu- Nov. 7, 1969 Germany ..P 19 56 035.1 ration [52] US. Cl ..57/52, 294/93 9 Claims, 2 Drawing Figures [51] Int. Cl. ..D0lh 9/00, B660 1/46 PATENTED FEB 6 I975 sum 1 or z In ventor:

INFLATABLE GRIPPER FOR HANDLING SPOOLS OF TEXTILE MACHINES BACKGROUND OF THE INVENTION This invention relates to a mandrel-like gripper assembly for engaging and firmly holding spools of textile machines and is of the type which may be introduced at least partially into the hollow interior of the spool. The gripper proper which projects beyond an associated support, is formed as a hollow body having a resilient wall that is radially expandable by a pressure medium admitted to the inside of the gripper for causing its expandable wall to be firmly clamped against the inner wall of the spool.

By spools there are meant any kind of transportable cores, bobbins or sleeves on which a yarn package may be wound and which are adapted to be internally grasped by an expandable gripper of the afore-outlined type.

In known structures, the gripper wall has the shape of a circular cylinder. It is a drawback of such structures that a relatively large pressure is needed for its expansion. Also, its cross-sectional rigidity is relatively slight in its expanded condition. Thus, in order to withstand the loads and stresses to which the gripper may be exposed, it has to be made of particularly high-strength, and hence expensive synthetic materials.

OBJECTS, SUMMARY AND ADVANTAGES OF THE INVENTION The objects of the invention are to provide improved grippers of the aforenoted type in which the disadvantages of known grippers no longer exist; which, particularly when used in automatic spool changing mechanisms of spinning or twisting machines, meet the requirements in a manner superior to grippers known heretofore; which have a superior operational safety and which may firmly and securely engage spools of widely varying inner diameters.

Briefly stated, according to the invention there is provided a gripper body of the aforenoted type, the expandable wall of which includes parallel, longitudinally extending and circumferentially spaced folds or creases.

It is an advantage of a gripper structure according to the invention that it is expandable by pressure that is smaller than that required for inflating grippers having a cylindrical wall. Consequently, the gripper structure according to the invention is exposed to lesser stresses and thus its life expectancy is greater. Further, under similar conditions, it may be expanded to a significantly greater extent than a cylindrical gripper having a comparable wall thickness. The longitudinal folds render the gripper wall more rigid when expanded so that it is more resistant to bending or buckling forces than grippers having a cylindrical wall structure. Such an increased rigidity is particularly advantageous in cases when the yarn, for some reason, has not been cut and the fully wound spool is moved away by the gripper from the spindle. In such instances the taut yarn exerts a pulling force on the 'spool. The increased rigidity of the gripper body, according to the invention, diminishes a lateral yielding of the gripper to such pulling force and thus not only prevents a wrong positioning of the spool which may cause damage thereto, but also causes the desired breakage of the yarn. Stated in different terms, by virtue of the increased rigidity of the gripper body, its resistance to the pulling of the yarn will cause breakage of the latter before the spool is pulled into an undesired, wrong lateral position. Because of the smaller stresses to which the gripper according to the invention is exposed, it may be made of a synthetic material of lesser strength which is less expensive and easier workable than the synthetic materials used heretofore for known cylindrical grippers.

Allthese advantages may be achieved without any significant additional expenses since the novel expandable gripper body may be manufactured in a single operational step by pressing or injection molding of a synthetic material, rubber or similar elastic or flexible material.

The invention will be better understood, as well as further objects and advantages will become more apparent, from the ensuing detailed specification of a preferred, although exemplary, embodiment taken in conjunction with the drawing.

BRIEF DESCRIPTION OF THE-DRAWING FIG. I is a partially sectional side elevational view of a preferred gripper assembly according to the invention, and

FIG. 2 is a sectional view along line IIII of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT completion of a yarn package wound on the spools, the

latter are firmly engaged by the grippers and, by means of an appropriate displacement of the gripper rail 17, are removed from the spindles and conveyed to discharge stations. Thereafter, preferably the same grippers firmly engage empty spools which, by virtue of an appropriate shift of the gripper rail 17, are moved to the spindles and inserted thereon. Such spool changing devices are well known and are therefore not described in greater detail.

The gripper assembly 10 includes a coupling member 11, a clamping sleeve 11' and a mandrel-like gripper body 12 made of a flexible elastic synthetic material.

The coupling member 11 has three functions: first, by means of its threaded terminal portion 14 it secures the entire gripper assembly 10 to the gripper rail 17; secondly, the collar portion 15 of the coupling member 11, in cooperation with the clamping sleeve' 11, firmly holds the gripper body 12 by its cylindrical terminal portion 35 and thirdly, by means of its throughgoing axial bore 16, the coupling member 11 admits pressurized fluid, preferably air, from the inner space 19 of gripper rail 17 into the inside of gripper body 12 for the purpose of inflating the same. In order to ensure a fluid tight connection between each gripper assembly and the gripper rail 17, between the latter and the associated clamping sleeve 11' there is inserted an O-ring 40. The inner space 19 of the gripper rail 17 is connected to a pressure source, not shown. In the drawing, the gripper body 12 is shown in a deflated condition in which it may be introduced with a clearance into and withdrawn from the inner space of a spool 23. By introducing pressure medium into the inner space 20 of the gripper body 12, the latter may be expanded until it firmly engages the inner wall 22 of the spool 23.

The gripper body 12 has a circumferential wall 29 and a conically narrowing terminal portion or wall 30 integral therewith. From the terminal wall portion 30 to the location indicated at 32 there extends a gripper body portion 33 which has an approximately constant wall thickness and which is inscribable in a cylindrical shell. This body portion 33 serves for gripping the spool and has, according to the invention, a plurality preferably 4-6 of longitudinally extending, circumferentially spaced folds or creases 13 which are disposed parallel to the gripper axis. As seen in FIG. 2, the wall portion 33 whichhas an undulated cross sec tion, is composed of a total of five identical axial folds 13. The axially parallel, circumferentially spaced elongated depressions or grooves formed by adjacent folds l3 taper both in the direction of the free tip of the gripper body and in the direction of the coupling member 11. On the one hand, the folds l3 terminate in the conical end portion 30, about midway from the beginning of this portion and its terminal tip, and, on the other hand, they terminate immediately below the clamping sleeve 11'. The gripper body 12 is preferably so designed that the wall'thicknesses are approximately constant even in those zones of the folds which adjoin the gripper wall portion 33.

Although it is usually preferred if the terminal por- It is, however, often a requirement that the gripper be capable of a limited transversal elastic deflection. This enables the gripper to automatically correct, by lateral deflection, any initial misalignment between the gripper and the spool during the introduction of the former in a deflated condition into the latter. For this reason, it is usually more advantageous to fixedly clamp radially expandable wall, the cross section of which having a c osed configuration surrounding said axis,

said wall including a plurality of axially parallel, circumferentially spaced folds.

2. An improvement as defined in claim 1, wherein the cross section of said wall in the zone of said folds has an undulated configuration.

3. An improvement as defined in claim 1, wherein, said wall has a substantially uniform thickness at least in the zone of said folds.

4. An improvement as defined in claim 1, wherein at least a portion of said wall that contains said folds is'inscribable into a cylinder.

5. An improvement as defined in claim 4, wherein at least said portion of said wall is formed of an elastic I material.

tion 30 is integral with the gripper body portion 33, it is feasible to make this terminal'portion separately, for example, of a rigid material.

'It is further within the scope of the invention to providea gripper body portion which has an undulated cross section and which is held at both ends by a unitary support means. By virtue of the rigid structure of the latter, the radial strength of the gripper is additionally increasedsince both ends of the gripper body portion are fixedly held.

6. An improvement as defined in claim 1, wherein the number of said folds is at least four.

7. An improvement as defined in claim 6, wherein the number of said folds is at most six.

8. An improvement as defined in claim 1, wherein said gripper body includes a free terminal portion ad- 40 joining said first-named portion of said wall; said folds extend into and terminate in said free terminal portion.

9. An improvement as defined in claim 1, wherein said gripper assembly includes means for securely holding said gripperv body, said gripper body includes a cylindrical wall portion axially adjacent said'folds and firmly clamped in saidlast-named means. i 

1. In an inflatable gripper assembly particularly for handling spools of textile machines, said gripper assembly being of the known type that is axially introduceable in a deflated condition into a spool and is inflatable therein to expand radially to firmly engage the inner wall of said spool, the improvement comprising a hollow gripper body having a longitudinal axis and a radially expandable wall, the cross section of which having a closed configuration surrounding said axis, said wall including a plurality of axially parallel, circumferentially spaced folds.
 1. In an inflatable gripper assembly particularly for handling spools of textile machines, said gripper assembly being of the known type that is axially introduceable in a deflated condition into a spool and is inflatable therein to expand radially to firmly engage the inner wall of said spool, the improvement comprising a hollow gripper body having a longitudinal axis and a radially expandable wall, the cross section of which having a closed configuration surrounding said axis, said wall including a plurality of axially parallel, circumferentially spaced folds.
 2. An improvement as defined in claim 1, wherein the cross section of said wall in the zone of said folds has an undulated configuration.
 3. An improvement as defined in claim 1, wherein said wall has a substantially uniform thickness at least in the zone of said folds.
 4. An improvement as defined in claim 1, wherein at least a portion of said wall that contains said folds is inscribable into a cylinder.
 5. An improvement as defined in claim 4, wherein at least said portion of said wall is formed of an elastic material.
 6. An improvement as defined in claim 1, wherein the number of said folds is at least four.
 7. An improvement as defined in claim 6, wherein the number of said folds is at most six.
 8. An improvement as defined in claim 1, wherein said gripper body includes a free terminal portion adjoining said first-named portion of said wall; said folds extend into and terminate in said free terminal portion. 